Expand 8 Click is a compact add-on board that contains a multi-port I/O expander with bi-directional input/outputs. This board features the MAX7317, 10-Port SPI-interfaced I/O expander with overvoltage and hot-insertion protection from Analog Devices. The MAX7317 provides microprocessors with 10 I/O ports rated to 7V. Each port can be individually configured as either an open-drain output or an overvoltage-protected Schmitt input that supports hot insertion. All port pins remain high impedance in Power-Down mode with up to 8V asserted on them. This Click board™ is intended for use as a port expander in system monitoring applications, industrial controllers, portable equipment, and many more.

Expand 8 Click is supported by a mikroSDK compliant library, which includes functions that simplify software development.

Expand 8 Click as its foundation uses the MAX7317, a general-purpose input/output (GPIO) peripheral from Analog Devices that provides 10 I/O ports, P0 to P9, controlled through a high-speed SPI-compatible serial interface. Each port, P0 to P9 can be configured as open-drain, current-sink outputs rated at 20mA maximum, or as CMOS inputs, or as open-drain outputs. Loads should be connected to a supply voltage no higher than 7V.

The MAX7317 contains ten 8-bit internal registers. These ten registers addressed as 0x00 - 0x09 control an I/O port each. Write 0x00 to the output register to set the port as a logic-low output, or 0x01 to set the port as a logic-high output or logic input.

Expand 8 Click communicates with MCU through a 16-bit 4-wire serial interface compatible with standard SPI, QSPI™, MICROWIRE™ guaranteed to operate at 35Mbps on its 3.3V power supply. During the Power-Up sequence, all control registers of the MAX7317 are in a reset state. Power-Up status sets I/O ports, P0 to P9, into a high impedance state and puts the device into Shutdown mode. The I/O ports P0–P9 remains high impedance with up to 8V asserted on them when the MAX7317 is powered down. Therefore, it can be used in hot-swap applications.

This Click board™ can be operated only with a 3.3V logic voltage level. The board must perform appropriate logic voltage level conversion before use with MCUs with different logic levels. However, the Click board™ comes equipped with a library containing functions and an example code that can be used, as a reference, for further development.

• Interface: SPI
• Compatibility: mikroBUS™
• Dimensions: 42.9 x 25.4mm
• Input Voltage: 3.3V
• Output Load Voltage P0 - P9: 7V
• Maximum Output Current: 20mA
• Operating Temperature Range: Min. -40°C, Typ. +25°C, Max. +125°C

• Schematic
• MAX7317 Datasheet
• mikroSDK
• GitHub